There is a Tibetan story about an old, blind Turtle who lives in the depths of the ocean. Once every thousand years, the turtle swims to the top of the sea, and sticks its head up through the waves, surfacing for air. Now imagine that there is a wooden ring floating somewhere on the surface of the ocean, and think of how rare it would be for the blind turtle, coming up for air once every thousand years, to put its head through the wooden ring. It is just that rare, say the Tibetans, for a being to gain human birth.
- 'Chop Wood, Carry Water'